Competition for phosphate between establishing plants of Lolium perenne and Trifolium repens under differing cultivation treatments in an upland pasture

Summary The relative uptake of phosphate, introduced as radioactive 32P into an Agrostis-Festuca hill land association in mid-Wales, was examined under two contrasting methods of cultivation: (i) complete cultivation, (ii) slot-seeding. Seedling plants of Lolium perenne S. 23 and Trifolium repens S. 184 were grown as pure stands and as binary mixtures with plants either 4 or 6 cm apart. Relative uptake of phosphate was higher under complete cultivation and, in the binary mixtures, clover accounted for 26% of the uptake only. The percentage of phosphate removed by each of the species when grown in mixtures remained constant over cultivation treatments. The significance of the results to agronomic practice is discussed.